Pressure actuated switch



Oct. 13, 1931. R PENN 1,827,102

PRES SURE ACTUATED SWITCH Oct. 13, 1931. p, PENN 1,827,102

PRESSURE ACTUATED SWITCH Filed May 2l, 1927 2 Sheets-Sheet 2 PatentedOct. 13, 1931 UNITED STATES PATENT oFFlc RALPH PENN, or DES MOINES,IOWA, AssIeNoR 'rOrENN ELECTRIC swI'rcrr co., YOI? Das MOINES, IOWA, ACORPORATION or IOwA PRESSURE ACTUATED SWITCH Application led Hay 21,1927. Serial No. 193,310.

The object of my invention is to rovide a pressure actuated switch forma ing and breaking an electric circuit employing in such switch amagnet and other parts so arranged that the circuit may be made orbroken with a positive snap action and thus eliminate any lingeringeffect, at the time the circuit is made or broken, the parts beingsimple, durable and comparatively inexpensive.

More particularly it is my object to provide a flexible actuatingmechanism, so that the magnet is effective and does: first, acceleratethe final movement of the armature when closing the circuit; and second,resist the opening movement of the armature against the fiexibleactuating parts to a degree suilicient to cause the circuit to befinally broken by rapid vsnap action.

Still a further object is to provide a switch actuated Vby either air orfluid pressure wherein an auxiliary contact member carried by anarmature arm will retain the contact and keep the circuit closed untilafter the main con act point has been broken and the armature carryingthe movable main contact member and the movable auxiliary contact memberis in rapid motion moving from the closed to the open position.

' Still another object is to provide an excess motion take-up betweenthe pressure operated lever Of the switch and the movable armaturemember wherein the contact is made without the danger of the levermoving too far and damaging the connecting parts between the lever andarmature mem- Still another object is to provide a magnet forfunctioning as a magnetic blow-out for all arcing that takes placeeither when closing or opening the circuit, which arcing always occursdirectly between the poles Of the ma et.

ith these and other objects in view, my invention consists in theconstruction, arrangement and combination of the various arts of mypressure actuated switch, wherey the objects contemplated are attained,as hereinafter more fully set forth, pointed out in my claims, andillustrated in the accompanying drawings, in which:

Figure 1 is a plan view of my pressure actuated switch with parts shownin section to better illustrate the operation thereof.

Figure 2 is a vertical sectional view taken on the line 2-2 of Figure 1.

Figure 3 is a plan view of the switch with portions of the cover platebroken away and illustrating the contacts in opened position.

Figure 4 is a plan view illustrating the auxiliary contacts as inengagement with 60 each other and the armature and main contactdisengaged.

Figure 5 illustrates a slightly modified form of mechanism for actuatingthe switch.

Figure 6 is a plan view of the switch illus- 65 rating the operatingparts in another posiion.

Figure 7 is a perspective view of the armature arm and Figure 8 is aperspective view of the 7 bracket upon which the armature arm ismounted.

In the accompanying drawin I have used l the reference numeral 10 to inicate generally a shell or casing in which the switch mechanism and theactuating parts are mounted. The shell or casing 10 includes a back wall12 having an open portion 14 adjacent the switch mechanism as willhereinafter be more so fully set forth.

The front side of the shell 10 is entirely open and'may be closed by acover plate 16. The cover plate 16 is designed to be held in position bya bolt or the like 18 fixed to the g5 therewith through which the air orfluids of 90 various kinds may pass into the control cas- Vithin thecontrol casing is mounted an expansible and contractible bellowsstructure 24 at one end. The bellows structure 24 is mounted upon aplate 26 secured to the control casing 20 for providing an air or liquidtight chamber 28 around the bellows 24.

A pin or shaft 30 is connected to the bellows 24 at the other end andhas a reciprocating movement when the bellows is expanded or contracted.The pin 30 is provided with a central screw threaded opening 32 forreceiving an adjusting screw 34.' The screw 34 has a pointed cap or head36 thereon.

It will be understood that the bellows 24 is expanded or contracted bthe pressure or vacuum to which the cham er 28 is subjected. Thisexpansion and contraction imparts movement to the pin 30 and ad'ustingscrew 34. The adjusting screw an pin project through an opening 40formed in the shell 10 as clearly illustrated in Figures 1 and 5 of thedrawings.

A bracket 42 is mounted upon one of the walls of the shell 10. A bellcrank lever A is pivoted upon the bracket 42 by means of a pivot pin orthe like 44. The bell crank lever A is formed with a substantiallyhorizontal arm 46 and a substantially vertical arm 48. The arms 46 and48 need not be horizontal or vertical and it is only for the 'purpose otclearly describing the operation of my device that I refer to them bysuch terms.

Upon the arm 46 ofthe bell crank lever A. I provide downturned ears orthe like 50 through which the pivot pin 44 extends for properly mountingthe entire bell crank lever A. The cap 36 of the adjusting screw 34,which is tapered so as to provide a sharp point, engages the undersideof the arm 46.

Movement of the pin 30 of the bellows 24 will impart movement to thebell crank lever A. AThe bell crank lever A is moved in one direction atleast by spring pressure which will hereinafter be more fully set forth.v

In order to limit the movement of the bell crank lever A, I provide alimiting device 52 which has a pair of spaced fianges 54 thereon. Theend of the arm 46 of the lever A is bifurcated and straddles thelimiting device 52 between the two flanges 54.

Movement of the lever A is thus restricted or limited within the rangeafforded by the two flanges 54 of the element 52. Upon the arm 46 of thelever A is mounted a disc or spring holder 56 resting upon a pointedsupport 58.

A coil spring 60 tending to normally expand has 'one' end restingagainst the disc 56 and its other end resting against a disc 62. Thedisc 62 is formed with a central screw threaded opening which receivesan adjusting screw 64. The adjusting screw 64 is mounted in the shell10.'

The tension applied upon the s ring 60 may be varied by simply rotatingthe entire spring at which time the disc 62 will travel either upwardlyor downwardly upon the adjusting screw 64. The tension upon the coilspring 60 may be varied and adjusted to meet the conditions under whichthe switch structure is arranged to be operated.

-Fromrthe construction of the parts ju'st described it will be seen thatcontraction of the bellows 24 will cause the pin 30 to move upwardly oragainst the bell crank lever A thus operating it in one direction andagainst the action of the spring 60.

When the bellows 24 expands, the s ring 60 will force the lever A tofollow the ownward movement of the pin 30 and cause the pin 30 and thehead 36 upon the adjusting screw 34 to remain in engagement with eachother.

I will now describe the switch mechanism wherein the'electric circuitmay be made or broken and which is operated through movement of the bellcrank lever A in either direction. An insulated plate or support 66 ispositioned within the shell between two of the wallsthereof and held inposition by screws 68.

Upon the support 66 I provide an armature bracket 70 which has a finger72 arranged to rest against the support 66. A bindlng post 74 extends'through an opening 76 formed in the finger 72 and through an opening 78formed in the support 66.

A nut 80 is mounted u on the post 74 and when tightened retains t ebracket 70 upon the support 66. The bracket 70 is also formed with apair of lugs 82 provided with central openings for receiving a pivot pin84 upon which an armature arm B is pivotally supported as will behereinafter more fully set forth.

Below the opening 78 in the support 66 I provide another opening 86wherein the position of the`bracket 70 may be changed relative to thesupport 66 upon which it is mounted.

The purpose of the two openings 78 and 86 for varying the position ofthe bracket 70 will be more fully described.

Upon the support 66 I mount a magnet 88 held in position by a retainingclip 90. A binding post 92 projects through the clip 9() and through thesupport 66 for holding the retaining clip and magnet 88 in operativeposition. The magnet 88 as illustrated in the drawings is of thehorseshoe type and may be adjusted or moved crosswise of the support 66.Other magnets may be used.

A nut 94 is positioned upon the post 92 and serves to retain the post 92in operative position relative to the su port 66. An auxiliary contact96 is carried y the retaining 'clip 90 and is centrally located betweenthe ends of the magnet 88 and may be said to be centrally located withinthe magnetic field of the magnet 88. j

The contact 96 is what may be termed a stationary auxiliary contact. Thebindinv post 92 makes contact with the contact point 96 through theretaining clip 90.v An auxiliar post 98 is mounted upon the support 66,and 1s connectedto the post 92 by a metal bar 100. j

A sleeve or the like 102 is carried by the post 98 and has an adjustingscrew 104 mounted therein. The adjusting screw 104 may be termed a fixedmain contact. The position of the screw 104 may, however, be adjustedand when once adjusted remains stationary.

The sup ly lines or wires 106 and 108 lead to the bin ing posts 74 and92 respectively. It will thus be seen that the wire 108 electrifies thepost 92, the bar 100 and thereby the post 98 and the main contact 104.rIhe auxiliary contact 96 is also electrified from the wire 108. Thewire 106 electrifies the post 74 and by means of a short wire 110, thearmature arm B.

The armature arm B comprises a pair of spaced arms 112 which areprovided with a pair of spaced openings 114. The upper openings 114 aredesigned to receive the pivot pm 84 of the bracket 70. The armature armB is thus pi'votally supported upon. the bracket 70 and relativel to thesupport 66. The armature arm B includes an elongated plate 116`having a.movable leaf spring 118 carried thereby. The leaf spring 118 isbifurcated near its lower end and carries a pair of movable contactpoints 120. The contact points 120 are designed to register with simi-.lar contact points 96 carried by the retaining clip 90.

In the drawings I have illustrated two Contact points 120 and in suchcase there is provided two contact points 96. The contact oints 120project through openings formed m the plate 116 of the armature arm B.The contact points 120 may be referred to as auxiliary movable contacts.The contacts 120 are capable of movement relative to and independent ofthe armature arm B.

The contacts 120 and 96 are located between i the poles of the magnet sothat the magnet functions to blow out any arcing that occurs when thecircuitis made or broken.

The fixed main contact 104 is arranged to coact or contact with a. mainmovable contact 105 carried by the armature arm B. The contact madethrough the member 104 and the armature arm B may carry the main load ofthe circuit. In order to move the armature arm B through actuation'ofthe lever A, it is necessary to provide a connection therebetween whichI will now describe in detail.

Upon the armature arm B substantially between the arms 112, is aninturned lug 122 having a central'threaded opening 124. The

opening 124 receives a screw 126. The screw 126 is 4formed with a head128 havin a groove or contracted neck therebelow. he screw 126 isverticallyv adjustable relative to the armature arm upon which it ismounted.

The lug 122 is positioned upon one side of the support 66 and does notinterfere therej with. Upon the lever A adjacent the pivot point thereofI mount a spring 130 preferably of the leaf type. The spring 130 extendsupwardly adjacent the vertical arm 48 of the lever A and has its upperend terminating near the upper end of the arm 48. The spring 130normally rests against the arm 48 and the two elements usually movetogether as a single construction.

The upper end of the spring 130 is provided with extensions 132 throughwhich is extended a pivot pin or the like 134. A connecting link or rod136 is received between j the extensions 132 and is connected to thepiv- The connection between the pin 140 and thev screw 126 enableseither of them to be adjusted within their bearings. The adjustment justreferred to enables the distance between the screw 126 and thespring'130 to be varied depending upon the particular mode or range ofoperation to which the switch structure is to be subjected.

The purpose of providing the spring 130 in place of directly connectingthe link 136 with the upper end of the arm 48, is one that addsmaterially to the successful operation of the entire switch structure.The spring 130 allows for excess operation of the lever A withouteffecting the arma-ture arm B.

After the Contact has been made, any further movement of the lever Acauses it to leave the spring 130 as illustrated in4 Figure 1 of thedrawings.

The limiting device 52 serves as a positive stop for the lever A. Thedesired position of the contact 104 and the armature arm B is such as tohave them contact just as the lever is about to engage the upper flange54 of the limiting device 52. It has been found very diicult to soconstruct the lever and armature arm as to have them engage the flange54 and contact 104 at the very same time.

Any additional movement of the lever after the armature has contactedwith the contact 104, is taken up by the spring 130 which allows the arm48 of the lever A to move away therefrom. Movement of the lever to breakthe contact operates against the spring 130 as though the parts wereinte al.

Upon the armature arm I provide a leaf 8 spring 142 which serves as ashock absorber for the armature when it strikes the shell 10. Insulatingmaterial 141 is placed within the shell adjacent the leaf spring 142.

In Figure 5 of the drawings I have shown the bell crank lever A as beingoperated through vacuum and in such case, a spring 143 is provided whichtends to contract and is connected at one end to the lever A and at itsother end to a screw member 144 mounted in the shell 10.

A nut 146 is positioned upon the screw 144 and by rotation of the nut146, I am able to adjust or change the tension of the spring 143. InFigure l o the drawin the link 136 is moved in the direction indlcatedby the arrow 148 for breaking the contact, while in Figure 6 of thedrawin s, the link 136 is moved in the opposite irection or in thedirection indicated by the arrow 150 to break the contact.

When the armature arm is moved to break the circuit by the link 136moving in the l direction indicated by the arrow 148, it is necessary tohave the pivot point of the arma- 80 ture arm above the upper end of thescrew 126. v, When the armature arm is moved to break the circuit bymovingthe link 136 in the direction indicated by the arrow 150, then thepivotal connection of the armature arm is positioned below the upper endof the screw 126. y

The positioning of the pivotal connection is governed by shifting thebracket 70 upon the support 66. The bracket 7 0 may be mounted upon thesupport 66 by using either of the openings 7 8 or 86. The position ofthe bracket 70 upon the support 66 determines whether the pivot rod orpin 84 engages with the upper pair of the openings 114 of the arms 45112 or the lower pair of openings 114.

When the bracket 70 is shifted upon the support 66 with the pivot pin.84 engaging the lower pair of o nings 114 of the arms 112 as illustratedin igure 6 of the drawings,`

the leaf spring 130 is secured to the opposite side `lof the verticalarm 48 of the bell crank lever A.

It will be noted that in Fi re 1 of the drawings, the leaf spring 130 1son one side of the arm 48 while in Figure 6, the same leaf spring 130 ison the other side of the same arm 48. In each case the position of thespring 130 relative to the arm 48 is such that the arm 48 moves with thespring 130 as a single structure when moving the armature B from theclosed circuit position to the open circuit position.

Practcal operation The switch as shown in Figure 1 of the 5 drawings,operates in the manner I will now describe in detail. The switch is inposition where the amature is in enga ment with the contact 104 and theelectric circuit is closed.

When the bellows 24 expands, it allows the circuit to be broken. Theexpanding bellows 24 allows the pin 30 to move downwardly or away fromthe bell crank lever A. The spring 60 retains the lever A and screw 34in en agement while the pin 30 is being moved ownwardly. Such movementforces the vertical arm 48 of the lever A to move the leaf spring Thismovement of the vertical arm 48 forces the link 136 in the directionindicated by the arrow 148. This movement swings the arma'- ture arm Bupon its pivot in a direction away from the contact 104.

It will be noted that when the contact 104 is in engagement with thearmature B, the spring 118 upon which the auxiliary contacts arecarried, is positioned as sprung away from the plate 116 of the armatureB. As the link 136 1s moved in the direction indicated by the arrow 148,it rst causes the armature B to break away from the contact 104 asillustrated in Figure 4 ofv the drawings. The auxiliary contacts 120 and96 are still in engagement with each other.

The different positions of the armature and the leaf spring 118, isclearly shown in Figures 1 and 4 of the drawings. It will be rememberedthat the electric circuit, when the parts are in position as illustratedin Figure 4 of the drawings2 will still be maintained through theauxilia contacts 120 and 96.

The movement o the link 136 which is caused by a positive but flexiblemovement, compels or forces the armature B to move away from the magnet88 and out of the effective magnetic field. Further movement of the link136 in the direction indicated by the arrow 148 causes the auxiliarycontacts 120 and 96 to be broken and the parts then assume the positionillustrated in Figure 3 of the drawings.

The ma et 54 retards the armature arm from brea 'ng away from thecontact 104 until the flexible connections between the armature andoperating lever have built up a force to overcome the magnetic influenceand thereafter the built up force is released thus imparting to thearmature arm a very rapid movement.

The armature arm when moving to open circuit position picks up andcarries away the auxiliary contacts 120 from the contacts 96. Therelease of the built up forces in the flexible connections as justdescribed accelerates the movement of the armature arm to open circuitposition.

During such movement the magnet 88 tends to hold the armature B againstthe pressure of the spring 60, the force of which is being allowed toact on the horizontal arm 46 of the bell crank lever A. When the forceexerted by the spring 60 overcomes the attraction of the magnet 88 forthe armature B the main circuit through the contact 104 and the armatureB will be. broken as clearly illustrated in Figure 4 of the drawings.

The armature B is now in a much weaker magnetic field and the forces ofthe spring 60 and the pressure within the control casing 20 will tend toequalize themselves which equalization does not occur until after theauxiliary contacts 96 and 120 have been separated. Incidentally theseauxiliary contacts will be broken quickly due to the momentum acquiredby the armature B after it has been moved out of the strongest portionof the magnetic field produced by the magnet 88y and due further to thefact that the forces of the v spring 60 and the actuating pressure inthe control casing 20 are not yet equalized.

Soon after the contacts 96 and 120 are separated, and before theequalization just mentioned takes place, the arm 46 has engaged thelower fiange 54 of the stop member 52 and the armature arm B is held inthe open circuit position illustrated in Figure 3 of the drawings. Whenmoving from the position shown in Figure 4 of the drawings, to the opencircuit position just mentioned, the spring 142 acts as a shock absorberfor the arm B and tends to eliminate vibration.

The magnet 88 when the armature B is being moved'to position where acircuit will be made, functions to draw or snap the armature arm Btowards its ends and in turn the electric circuit is caused byengagement of the auxiliary contacts 96 and 120 and then the armaturearm B with the cont-act 104.

The snap movement imparted to the armature arm B through the influenceof the magnet 88 causes a positive engagement ofthe contacts 96 and 120and of the contact 104 with the armature arm B. The leaf spring 130takes care of the continued movement of the bell crank lever A after thecircuit is made and allows the arm 46 of the lever to move to positionengaging the lower flange 54 of the stop 52. I

In Figure 6 of the drawings, the breaking of the circuit takes place bmovement of the link 136 in the direction indicated by the arrow 150.The operation except for the direction of the movement, is exactl thesame as that described in connection with Figure 1 of the drawings.

The armature arm B is first disengaged from the contact 104. Themagnetic fielda of the magnet 88 influences the armature B in the sameway as described in connection with Figure 1, thus disengaging thecontacts 120 from the contacts 96. v

The lever A may be actuated by either fluid or air pressure or vacuumoperated or operated under any conditions that will give to it movement,thus in turn causing the armature arm to be actuated for making orbreaking an electric circuit. The magnet itself, is adjust-able as isthe contact 104 and the screw 126. The adjustment of the screw 126varies the distance between the pivot of the armature arm and theconnection between the screw 126 and link 136.

Such adjustment varying the effect of the `magnet as to point yof oeration of the armavice without departing from the real spirit andpurpose of my invention, and it is my intention to cover by my claims,any modified forms of structure or use of mechanical equivalents, whichmay be reasonably included within their scope.

I claim as my invention:

1. In an automaticv controlling device, a a power unit, a switch unitincluding an armature arm and an operative connection between said unitsincluding a lever adapted to be moved by the power unit and a connectionbetween said lever and said armature arm, said connection when moving inone direction serving to rigidly connect the arm and lever together andwhen moving in the opposite direction allowing independent movement ofthe lever relative to said armand means for varying the differential asto when said armature arm operates.

2. In an automatic controlling device, a.

power unit, a switch unit andan operative connection between said unitsincluding a lever adapted to be moved by the power unit and a connectionbetween said lever and said switch unit for operating the latter u onmovement of the former, a spring secur to one side of said lever andnormally in contact herewith, said connection being connected with saidspring whereby the lever positively pushes the connection in onedirection and the spring pulls the connection in the other direction.

3. In an automatic controlling device, a power unit, a switch4 unit andan operative connection between said units including a member adapted tobe moved by the power unit and a connection between said member and saidswitch unit for operating the latter upon movement of the former, aspring secured to one side of said member and normally in contacttherewith, said connection being connected with said spring wherebj7 themember positively pushes the connectlon in one direction but may leavethe connection under tension of said spring when moving in an oppositedirection. v

4. In an automatic controlling device2 a power unit, a. switch unit andan operatlve 5 connection between said units including a lever adaptedto be moved by the power unit and a connection between said lever andsaid switch unit for operating the latter u on movement of the former, aspring secure to one side of said lever and normall in contact therewithand an ear carrie by the spring and connected with the connection.

Des Moines, Iowa, May 16, 1927.

RALPH PENN.

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